/**
 * String,Array,Map,Set,Arguments,NodeList....
 * - for of,展开运算符
 */
const str = 'hello world'

const iteratorStr = str[Symbol.iterator]()
console.log(iteratorStr.next())
console.log(iteratorStr.next())
console.log(iteratorStr.next())
console.log(iteratorStr.next())
console.log(iteratorStr.next())
console.log(iteratorStr.next())
console.log(iteratorStr.next())
console.log(iteratorStr.next())
console.log(iteratorStr.next())
console.log(iteratorStr.next())
console.log(iteratorStr.next())
console.log(iteratorStr.next())
